Air traffic control courses
In every major city of the world, you can find institutions which train potential air traffic controllers, by offering courses of different lengths of time. Do some research in your region about air traffic control institutions and get admitted in the next course. The later part of the training will include practical exercises, which should definitely go a long way in helping you understand how air traffic control works.
You have to imagine the airspace in order to understand how air traffic works. Divide the airspace in precise sectors in your imagination, keeping in mind that the flow of departing and approaching aircrafts is handled by the Terminal Radar Approach Control (TRACON) sections. You must also take into account the fact that larger areas of enroute traffic are controlled by Air Route Traffic Control Center (ARTCC).
Consult a senior air traffic controller
There is no alternate to experience. If you know someone in your social circle who has ever worked as an air traffic controller, consult him or her and extract as much information as possible. The first hand information should be really helpful for you.
Work as an assistant air traffic controller
Once you have done the required courses, it is highly recommended that you work as an assistant to a professional air traffic controller. This experience will really help you understand air traffic control.
In the modern world, you can find any information over the internet. You can search online about air traffic control and try to understand how the system works.
Enhance your communication skills
In order to understand the air traffic control system, you must possess communication skills of the highest level as an air traffic controller has to communicate with the pilots and other officials on regular basis.